PolicyStatement Class

 

Represents the statement of a CodeGroup describing the permissions and other information that apply to code with a particular set of evidence. This class cannot be inherited.

Namespace:   System.Security.Policy
Assembly:  mscorlib (in mscorlib.dll)

System.Object
  System.Security.Policy.PolicyStatement

[SerializableAttribute]
[ComVisibleAttribute(true)]
public sealed class PolicyStatement : ISecurityPolicyEncodable, 
	ISecurityEncodable

NameDescription
System_CAPS_pubmethodPolicyStatement(PermissionSet)

Initializes a new instance of the PolicyStatement class with the specified PermissionSet.

System_CAPS_pubmethodPolicyStatement(PermissionSet, PolicyStatementAttribute)

Initializes a new instance of the PolicyStatement class with the specified PermissionSet and attributes.

NameDescription
System_CAPS_pubpropertyAttributes

Gets or sets the attributes of the policy statement.

System_CAPS_pubpropertyAttributeString

Gets a string representation of the attributes of the policy statement.

System_CAPS_pubpropertyPermissionSet

Gets or sets the PermissionSet of the policy statement.

NameDescription
System_CAPS_pubmethodCopy()

Creates an equivalent copy of the current policy statement.

System_CAPS_pubmethodEquals(Object)

Determines whether the specified PolicyStatement object is equal to the current PolicyStatement.(Overrides Object.Equals(Object).)

System_CAPS_pubmethodFromXml(SecurityElement)

Reconstructs a security object with a given state from an XML encoding.

System_CAPS_pubmethodFromXml(SecurityElement, PolicyLevel)

Reconstructs a security object with a given state from an XML encoding.

System_CAPS_pubmethodGetHashCode()

Gets a hash code for the PolicyStatement object that is suitable for use in hashing algorithms and data structures such as a hash table.(Overrides Object.GetHashCode().)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_pubmethodToXml()

Creates an XML encoding of the security object and its current state.

System_CAPS_pubmethodToXml(PolicyLevel)

Creates an XML encoding of the security object and its current state.

A PolicyStatement consists of a set of granted permissions, and possible special attributes for the code group.

Policy statements are typically used as the return value of a Resolve operation on a PolicyLevel.

The following code example shows the use of members of the PolicyStatement class

using System;
using System.Security;
using System.Security.Policy;
using System.Security.Principal;
using System.Security.Permissions;

class Members
{
    [STAThread]
    static void Main(string[] args)
    {
        // Create two new policy statements.
        PolicyStatement policyStatement = firstConstructorTest();
        PolicyStatement policyStatement2 = secondConstructorTest();

        // Add attributes to the first policy statement.
        policyStatement.Attributes = PolicyStatementAttribute.All;

        // Create a copy of the first policy statement.
        PolicyStatement policyStatementCopy = createCopy(policyStatement);
        addXmlMember(ref policyStatementCopy);

        summarizePolicyStatment(policyStatement);
        Console.WriteLine("This sample completed successfully; " +
            "press Enter to exit.");
        Console.ReadLine();
    }

    // Construct a PolicyStatement with an Unrestricted permission set.
    private static PolicyStatement firstConstructorTest() 
    {
        // Construct the permission set.
        PermissionSet permissions 
            = new PermissionSet(PermissionState.Unrestricted);
        permissions.AddPermission(
            new SecurityPermission(SecurityPermissionFlag.Execution));
        permissions.AddPermission(
            new ZoneIdentityPermission(SecurityZone.MyComputer));

        // Create a policy statement based on the newly created permission
        // set.
        PolicyStatement policyStatement = new PolicyStatement(permissions);

        return policyStatement;
    }

    // Construct a PolicyStatement with an Unrestricted permission set and
    // the LevelFinal attribute.
    private static PolicyStatement secondConstructorTest()
    {
        // Construct the permission set.
        PermissionSet permissions =
            new PermissionSet(PermissionState.Unrestricted);
        permissions.AddPermission(
            new SecurityPermission(SecurityPermissionFlag.Execution));
        permissions.AddPermission(
            new ZoneIdentityPermission(SecurityZone.MyComputer));

        PolicyStatementAttribute levelFinalAttribute = 
            PolicyStatementAttribute.LevelFinal;

        // Create a new policy statement with the specified permission set.
        // The LevelFinal attribute is set to prevent the evaluation of lower
        // policy levels in a resolve operation.
        PolicyStatement policyStatement =
            new PolicyStatement(permissions, levelFinalAttribute);

        return policyStatement;
    }

    // Add a named permission set to the specified PolicyStatement.
    private static void AddPermissions(ref PolicyStatement policyStatement)
    {
        // Construct a NamedPermissionSet with basic permissions.
        NamedPermissionSet allPerms = new NamedPermissionSet("allPerms");
        allPerms.AddPermission(
            new SecurityPermission(SecurityPermissionFlag.Execution));
        allPerms.AddPermission(
            new ZoneIdentityPermission(SecurityZone.MyComputer));
        allPerms.AddPermission(
            new SiteIdentityPermission("www.contoso.com"));

        policyStatement.PermissionSet = allPerms;
    }

    // If a class attribute is not found in the specified PolicyStatement,
    // add a child XML element with an added class attribute.
    private static void addXmlMember(ref PolicyStatement policyStatement) 
    {
        SecurityElement xmlElement = policyStatement.ToXml();
        if (xmlElement.Attribute("class") == null)
        {
            SecurityElement newElement = 
                new SecurityElement("PolicyStatement");
            newElement.AddAttribute("class", policyStatement.ToString());
            newElement.AddAttribute("version","1.1");

            newElement.AddChild(new SecurityElement("PermissionSet"));

            policyStatement.FromXml(newElement);

            Console.Write("Added the class attribute and modified its ");
            Console.WriteLine("version number.\n" + newElement.ToString());
        }
    }

    // Verify that the type of the specified object is a PolicyStatement type
    // then create a copy of the object.
    private static PolicyStatement createCopy(Object sourceObject)
    {
        PolicyStatement returnedStatement = new PolicyStatement(null);
        // Compare specified object type with the PolicyStatement type.
        if (sourceObject.GetType().Equals(typeof(PolicyStatement)))
        {
            returnedStatement = getCopy((PolicyStatement)sourceObject);
        }
        else
        {
            throw new ArgumentException("Expected the PolicyStatement type.");
        }

        return returnedStatement;
    }

    // Return a copy of the specified PolicyStatement if the result of the
    // Copy command is an equivalent object. Otherwise, return the
    // original PolicyStatement object.
    private static PolicyStatement getCopy(PolicyStatement policyStatement)
    {
        // Create an equivalent copy of the policy statement.
        PolicyStatement policyStatementCopy = policyStatement.Copy();

        // Compare the specified objects for equality.
        if (!policyStatementCopy.Equals(policyStatement))
        {
            return policyStatementCopy;
        } 
        else 
        {
            return policyStatement;
        }
    }

    // Summarize the attributes of the specified PolicyStatement on the
    // console window.
    private static void summarizePolicyStatment(
        PolicyStatement policyStatement)
    {
        // Retrieve the class path for policyStatement.
        string policyStatementClass = policyStatement.ToString();

        int hashCode = policyStatement.GetHashCode();

        string attributeString = "";
        // Retrieve the string representation of the PolicyStatement
        // attributes.
        if (policyStatement.AttributeString != null)
        {
            attributeString = policyStatement.AttributeString;
        }

        // Write a summary to the console window.
        Console.WriteLine("\n*** " + policyStatementClass + " summary ***");
        Console.Write("This PolicyStatement has been created with hash ");
        Console.Write("code(" + hashCode + ") ");

        Console.Write("and contains the following attributes: ");
        Console.WriteLine(attributeString);
    }
}
//
// This sample produces the following output:
//
// Added the class attribute and modified the version number.
// <PolicyStatement class="System.Security.Policy.PolicyStatement"
//                  version="1.1">
//    <PermissionSet/>
// </PolicyStatement>
// 
// *** System.Security.Policy.PolicyStatement summary ***
// PolicyStatement has been created with hash code(20) containing the
// following attributes: Exclusive LevelFinal
// This sample completed successfully; press Enter to exit.

.NET Framework
Available since 1.1

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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